Various types of ovens or food warming apparatus are used in a wide variety of applications, particularly in the food preparation and distribution fields. Such apparatus may range from a completely closed oven to an open-front oven to a pass thru oven which is open at both its front and rear ends. For instance, in high volume restaurants or similar establishments, various menu items are precooked, and the precooked items are held in warming ovens to maintain the temperature of the items for serving to a customer shortly thereafter. An example is a common sandwich. The sandwich may include a meat component and bread component, with the meat component being precooked and the bread component being pre-toasted, for instance. These precooked components are temporarily held in separate trays which are placed in ovens within which the temperatures of the components are maintained until the components are assembled and prepared as the final menu item for serving to the customer. The ovens sometimes are called staging cabinets or holding cabinets. They do not heat the precooked food components up to a given temperature, but they maintain or hold the prescribed precooked temperature of the components.
One of the problems in using food warming apparatus of the character described above is that the food components have a tendency to lose their prescribed moisture content while being temporarily held in food trays in the warming apparatus. Various sealing systems have been used to seal the food trays to contain the moisture of the food products therewithin. For instance, a food tray may simply be provided with a sealing cover. However, the cover often loses its seal, and the cover creates an extraneous component which must "travel" with the food tray and cause space problems as well as efficiency problems. Seals have been provided within the ovens themselves, but the seals often lose their effectiveness during use because no compensation is made for wear of the sealed components over their normal life. They also are not cost-effective and do not assure proper positioning of the food trays.
The present invention is directed to solving these problems by providing various improvements in food warming apparatus for sealing food trays and maintaining temperature and moisture control over food products held within the trays without undue labor costs.